What Causes Pain In Abdomen Along With Nausea?

I have not had an appetite for over a month and I have had nausea every day. 2 weeks ago I woke up with severe abdominal pain from my belly button to my upper stomach. I vomited for 2 hours and since then I have been in mild pain, and the moderate pain comes and goes. I have only been able to eat very little or just a few bites of food once a day. Then my upper stomach hurts worse and the nausea gets worse to. My stomach is empty yet I feel full.